While major automakers rush to promote the next level of autonomous features and release videos of hand-free driving, serious questions have been raised about whether autonomous vehicles will be able to safely co-exist with bicyclists and pedestrians.

Heather Knight, an expert in human-robot interfaces with a PhD from the Robotics Institute at Carnegie Mellon University, recently published a provocatively-titled essay: “Tesla Autopilot Review: Bikers Will Die.” While others have questioned whether the situation is quite so dire, her test drive of a Tesla found that the Situational Awareness Display only recognized one percent of bicycles and around 30 percent of cars. Her conclusion was that the autopilot functions are nowhere near ready to be used in an environment where bicyclists are going to be sharing the road.

Knight points out that the Situational Awareness Display is intended only to show what the car is seeing, so it actually points out the shortcomings of the system. For that, Knight says it is her favorite feature. “Providing the driver an accurate mental model of the system probably saves lives, and robots in general would benefit from communicating their limitations to people.” At the same time, she worries that drivers may become complacent and forget that the car is actually not seeing everything.

Other writers have pointed out that bicycles are a particularly hard puzzle for programmers to crack. They come in many different sizes and styles, including children’s sizes, cargo bikes, recumbents, and parents with children or groceries in tow. Bicyclists also do not quite operate like cars, nor do they quite operate like pedestrians. Bicycles are narrow and very maneuverable—unlike cars—and bicyclists can quickly accelerate or change lane position, leading them to be less predictable for computers. Google’s June 2016 self-driving car report acknowledges these challenges, but says it is dedicated to improving the systems. “It helps to have a number of avid cyclists on our engineering team!” they write.

These are not just theoretical problems, as video of a Nissan LEAF in autonomous mode overtaking a bicyclist shows. The car passes the bicyclist with less than the required passing distance despite the fact that the car’s display shows it detected the bicycle. The pass is so close that the French journalist in the car expresses concern at how close they passed.

On the more dystopian extreme, writers are concerned that pressures to make autonomous vehicles both ubiquitous and efficient will lead to restrictions on any road user not able to be detected by AVs, including not just drivers of older vehicles, but also pedestrians and bicyclists. They warn that we are just now reconnecting our cities and removing barriers such as elevated freeways that divided neighborhoods and made walking and biking difficult or dangerous. Dedicated AV roadways might be even harder to cross than larger arterials because, without traffic signals, there will be few breaks in traffic.

While AVs can certainly operate more safely than humans in many circumstances, it will be imperative to consider all road users as the technology develops. Attentive human drivers will still be needed until those problems are solved.